Add test for alias exact match over prefix

tests/test_prefix_matching.py

@@ -213,3 +213,23 @@ async def test_prefix_match_with_args(player, clean_registry):
     output = "".join([call[0][0] for call in player.writer.write.call_args_list])
 
     assert "Handler called with args: the floor" in output
+
+
+@pytest.mark.asyncio
+async def test_alias_exact_match_over_prefix_collision(player, clean_registry):
+    """Test alias exact match wins over prefix when otherwise ambiguous."""
+    commands.register(
+        CommandDefinition(
+            name="look", aliases=["l"], handler=dummy_handler, mode="normal"
+        )
+    )
+    commands.register(
+        CommandDefinition(name="list", handler=dummy_handler, mode="normal")
+    )
+
+    await commands.dispatch(player, "l")
+    output = "".join([call[0][0] for call in player.writer.write.call_args_list])
+
+    # Should call handler (exact match on alias), not show ambiguous
+    assert "Handler called" in output
+    assert "or" not in output